1. Field of Invention
The present disclosure relates generally to multi-tasking multi-processor environments, and in particular, to managing recovery and control of a communications link via out-of-band signaling.
2. Description of Background
When operating a communications link in a multi-tasking multi-processor environment, numerous failures can occur and there are a variety of ways in which the communication link can be recovered. For example, in the existing coupling technologies for a multitasking multi-processor environment, each channel is a separate real hardware connection. In these environments, there is hardware support for handling operations on either the channel or the buffer connection level. Operations of this sort include handling timed out or canceled operations. If there is a problem with the entire channel, then the entire link can be taken through recovery with hardware assists.
In the case of the new coupling technology based upon industry standard Infiniband, multiple channels are emulated across a single physical link, and therefore, there is no hardware assist that can be called upon to aid in the recovery of a failed communication link. Further, the data flow design uses pre-defined sequences of resources made available to send and receive messages across any individual virtual connection. If an unexpected message is received, it causes the connection to go into error. This prevents sending a cancel message on the individual buffer connection. Similar problems exist in the handling of channel operations.